Relativistic Broadening Effect on Application of Electron Cyclotron Emission Measurements to High Temperature Tenuous Tokamak Plasma

Satō, Masayasu; Ishida, S; Isei, N.

doi:10.1143/jpsj.62.3106

Cited by 17 publications

(5 citation statements)

References 7 publications

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“…The calculation method is the same as that in ref. 7, basically. The radiation transfer equation is solved in a slab model under the following assumptions.…”

Section: Radiation Transfer Equationmentioning

confidence: 99%

Effects of Relativistic and Absorption on ECE Spectra in High Temperature Tokamak Plasma

Satō

Isayama

2007

Plasma and Fusion Research

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Using the extended Trubnikov's expression for the fully relativistic Maxwellian in the case of oblique propagation to the magnetic field (B t ), electron cyclotron emission (ECE) spectra are calculated in a high temperature (T e ) tokamak plasma. We investigate the ECE by changing the angles between the sight line and the equatorial plane or B t direction. Feature of ECE spectra can be interpreted from the viewpoints of relativistic, Doppler and absorption effects. The downshift frequency variation due to the relativistic effect in the high field side (HFS) observation is bigger than that in the low field side observation. Absorption at the HFS plasma results in the deep dip at the HFS of fundamental, second and third harmonics in the ECE spectra. For the vertical observation, in the case of optically thin case, ECE spectra are similar to the emissivity profile, and when electron density (n e ) is higher, ECE spectra are modified due to the absorption in plasma. Since the B t , n e , T e increase in the case of the SlimCS DEMO reactor, the ECE spectra expands to high frequency emission (∼2000 GHz). So, ECE detector in the case of Fourier transform spectrometer system should be modified from present liquid He cooled InSb detector because of the detection of high frequency emission.

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“…The calculation method is the same as that in ref. 7, basically. The radiation transfer equation is solved in a slab model under the following assumptions.…”

Section: Radiation Transfer Equationmentioning

confidence: 99%

Effects of Relativistic and Absorption on ECE Spectra in High Temperature Tokamak Plasma

Satō

Isayama

2007

Plasma and Fusion Research

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“…It is important to study the relativistic effect on waves since it can change the dynamics of plasma in both the laboratory (fusion experiments) and astrophysical environments (white dwarf, neutron stars). The fusion experiment like ITER (International Thermonuclear Experimental Reactor) is the best example of a relativistic plasma where a particle can achieve relativistic velocity due to heating which is necessary to attain the temperature required for fusion [7][8][9][10][11]. Also, the synchrotron emission observed from radio galaxies and high energy x-rays and γ-rays from these sources confirm the existence of relativistic electrons in these naturally occurring plasma environments [12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Variation in the propagation characteristics of extraordinary mode with density, magnetic field and temperature in a relativistic plasma environment

Ali¹,

Khan²

2022

Phys. Scr.

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Propagation characteristics of extraordinary mode (perpendicularly propagating electromagnetic wave which is partly transverse and partly longitudinal known as X-mode) are examined in a relativistic, weakly relativis- tic and non-relativistic plasma environment for various density to magnetic field ratio ( ωpe/ωce ). The dispersion relation for X-mode is derived by using the relativistic kinetic model and employing Maxwell-Juttner distribution function. The integrals involved in the calculation are evaluated by using numerical quadrature approach. The mass dependent quantities like the cyclotron frequency and the plasma frequency will change by introducing sufficiently high temperature for which η = mc2 kB T < 1. This will effect significantly the propagation characteristics of X-mode. As the relativistic effects increase, the absorption at cyclotron frequency reduces and the dispersion characteristics of plasma vanishes. With the increase in the density or decrease in the magnetic field, the upper hybrid frequency and the right cutoff frequency shifted to a higher value, altering the propagation region.

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“…Furthermore, cutoff layers can become flat or even hollow due to cutoff frequency downshifts, thereby limiting core access [16]. Relativistic effects also broaden the electron cyclotron absorption region [2,17], causing increased absorption of the launched reflectometry probe radiation which also can potentially limit accessibility to the core plasma [2,3].…”

Section: Introductionmentioning

confidence: 99%

Relativistic effects on reconstruction of density profiles via reflectometry in ITER and potential for electron temperature measurements

Zeng¹,

Peebles²,

Doyle³

et al. 2007

Plasma Phys. Control. Fusion

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Relativistic effects on reflectometry density profile measurements have been evaluated for planned ITER operating scenarios. Standard X-mode, right-hand cutoff reflectometry reconstruction can produce large errors (up to 35% for T e (0) = 24 keV plasmas) in high-temperature ITER plasmas if relativistic effects are ignored. It will therefore be essential to account for these effects in ITER. The errors created in density profile reconstruction have been analysed using simulated temperature profiles, including uncertainties, as an input to a standard inversion routine. Modelling using random errors with maxima of ±10% across the electron temperature profile leads to errors in the inverted density profile ranging from zero at the edge to a maximum RMS error of ∼1% at the magnetic axis. In addition to this, a novel iterative inversion technique is demonstrated which eliminates the dependence on external T e information and allows T e itself, and hence electron pressure P e , to be extracted from the reflectometry measurement. The new technique utilizes phase data from both Oand X-mode propagation and has been successfully demonstrated numerically in peaked plasma profiles, as well as in the edge pedestal region. Integration of this novel approach with other planned measurement systems will serve to improve confidence in electron density and temperature measurements in ITER.

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Relativistic Broadening Effect on Application of Electron Cyclotron Emission Measurements to High Temperature Tenuous Tokamak Plasma

Cited by 17 publications

References 7 publications

Effects of Relativistic and Absorption on ECE Spectra in High Temperature Tokamak Plasma

Effects of Relativistic and Absorption on ECE Spectra in High Temperature Tokamak Plasma

Variation in the propagation characteristics of extraordinary mode with density, magnetic field and temperature in a relativistic plasma environment

Relativistic effects on reconstruction of density profiles via reflectometry in ITER and potential for electron temperature measurements

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